At least to me this doesn't look like it's at all caused by a userspace interpretation problem, it's caused only by this intel_backlight interface. It's defaulting to the maximum value it can be set to (4882).
* The button presses do actually translate into the values of /sys/class/backlight/acpi_video0/brightness changing between 0 and 15 as they should. Manually putting any numbers into /sys/class/backlight/intel_backlight/brightness smaller than max_brightness allows the ACPI video control to work*. Now most values above 0 set for intel_backlight seem to cause a horrible flicker on the screen as the ACPI values are changed. I compared to another machine with a properly functioning backlight control, and it's defaulting to a more sane 118 (out of max 976) on it's intel_backlight/brightness value. So for whatever reason, the intel_backlight value that is defaulted on this laptop is 4882. ** Package changed: gnome-power-manager (Ubuntu) => linux (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/954661 Title: backlight brightness not adjustable by default on Dell XPS 13 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/954661/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
